Automatically operable centerless grinder



A. H. TOMPKINS AUTOMATICALLY OPERABLE CENTERLESS GRINDER Filed March 24,1959 July 4, 1961 5 Sheets-Sheei l NNN lwmw INVENTOR. TOM P K INS ALBERTH- ATTORNEYS y 1961 A. H. TOMPKINS 2,990,656

AUTOMATICALLY OPERABLE CENTERLESS GRINDER Filed March 24, 1959 F'IG-3 5Sheets-Sheet 2 ."I iAlifil-liff INVENTOR.

A-r'r'oRNEYs July 4, 1961 A. H. TOMPKINS AUTOMATICALLY OPERABLECENTERLESS GRINDER Filed March 24, 1959 5 Sheets-Sheet 5 AA h y M W 0 cM A 3 M 3 0 WW 1 2 N T MER M MO) mm a a 1 Q 7 I W 0 M a a M k 00 II 7Mnk-L F w I I 0. II II 8 m 3 a VTL p 3 Mu, M w a r z z \M h 4 M a 2 3 w 5Z w 5 3 i 1 L AA INVENTOR ALBERT H- 'TOMFKINS ATTORNEYS United StatesPatent 2,990,656 AUTOMATICALLY OPERABLE CENTERLESS GRINDER Albert H.Tompkins, East Longmeadow, Mass, assignor to Van Norman Industries,Inc., Springfield, Mass., a corporation of Massachusetts Filed Mar. 24,1959, Ser. No. 801,541 11 Claims. (Cl. 51-103) This invention relates tocenterless grinders and, more particularly, to a centerless grinder ofthe type which is adapted to be operated automatically to grind a mumber of like workpieces in succession.

It is the general object of the invention to provide a centerlessgrinder of the above-mentioned type which may be readily adapted forthrough-feed grinding of a wide variety of types of workpieces.

Another object of the invention is to provide an improved automaticallyoperable loading apparatus in a centerless grinder of the type referredto, the said apparatus being adapted to handle elongated workpieces ofvarious sizes and shapes and to feed the same to the grinding throatbetween the grinding and regulating wheels in succession for athrough-feed grinding operation.

A further object of the invention is to provide an improved through feedmethod of grinding elongated workpieces to non-uniform diametersthroughout their lengths, the said method involving the delivery of theworkpieces to the grinding throat for a through-feed grinding operationand the upward removal of the workpieces from the grinding throat whenthey have advanced to a preselected position therein.

A still further object of the invention is to provide in a centerlessgrinder an automatically operable unloading apparatus which is adaptedto cooperate with an automatically operable loading apparatus toimplement the above-mentioned improved method for grinding non-uniformworkpieces.

The drawings show a preferred embodiment of the invention and suchembodiment will be described, but it will be understood that variouschanges may be made from the construction disclosed, and that thedrawings and description are not to be construed as defining or limitingthe scope of the invention, the claims forming a part of thisspecification being relied upon for that purpose.

Of the drawings:

'FIG. 1 is a fragmentary top plan view of a centerless grinding machineembodying the present invention;

FIG. 2 is a fragmentary side elevational view of the grinding machinetaken generally as indicated by the line 22 of FIG. 1;

FIG. 3 is an enlarged longitudinal vertical section taken as indicatedby the line 33 of FIG. 1 and showing the loading apparatus of thegrinding machine;

FIG. 4 is an enlarged horizontal sectional view of the loading apparatustaken as indicated by the line 44 in FIG. 2;

FIG. 5 is a transverse sectional view of the loading apparatus taken asindicated by the line 5-5 in FIG. 3;

FIG. 6 is another transverse sectional view of the loading apparatustaken as indicated by the line 6-6 in FIG. 3;

FIG. 7 is an enlarged fragmentary top plan view showing portions of thegrinding and regulating wheels of the grinding machine with a workpieceof non-uniform diameter located in the grinding throat;

FIG. 8 is a stepped horizontal sectional view of the unloading apparatusof the grinding machine taken as indicated by the line 88 in FIG.

FIG. 9 is a longitudinal vertical section taken as indicated by the line9-9 in FIG. 8 and showing a portion of the unloading apparatus;

FIG. 10 is a view of the unloading apparatus taken as indicated by theline Ill-10 in FIG. 8; and

FIG. 11 is a schematic wiring diagram illustrating a portion of theelectrical control system of the grinding machine.

Referring to the drawings, and more particularly to FIGS. 1 and 2thereof, it will be observed that the centerless grinding machineembodying the invention comprises three main sections, namely, a centralgrinding and regulating wheel section 10, a front section 12 comprisinga loading apparatus and a rear section 14 comprising an unloadingapparatus. In operation of the machine, workpieces proceed from thefront of the machine longitudinally toward the rear thereof (right toleft in FIGS, 1 and 2). A machine operator stands at the front of themachine toward its left-hand side so as to face diagonally the rear endsof the workpieces as they pass through the machine. A control panel 16containing the control switches and buttons for automatic operation ofthe machine is conveniently accessible in front of and to the right ofthe machine operator in this position.

The central grinding and regulating wheel section 10 of the machine maybe conventional and is shown as ineluding a grinding wheel 18 and aregulating wheel 20. The grinding wheel 18 (partially shown) issupported for rotation about a longitudinal axis at the left-hand sideof the machine as viewed from the front, and the regulating wheel 20(also partially shown) is supported for rotation about a longitudinalaxis spaced transversely from the grinding wheel axis at the right-handside of the grinding machine. Defined by and between said wheels is theusual grinding throat in which workpieces are supported by aconventional work supporting blade 24 and engaged in opposedrelationship by the wheels 18 and 20. Conventional operating means drivethe grinding and regulating wheels 18 and 20 and said wheels are adaptedfor various adjustments in accordance with conventional practice, one ofsaid adjustments being the usual tilt adjustment of the regulating wheelspindle which is utilized in drawing workpieces through the grindingthroat in through-feed grinding. operations. Illustration anddescription of the conventional operating means and the means foraccomplishing the various adjustments of the grinding and regulatingwheels are not deemed necessary for an understanding of the inventionand are therefore not included herein. For like reasons, otherconventional elements such as wheel truing or dressing devices andcoolant systems are not shown or described.

In FIG. 2 the grinding machine central section 10 is shown as alsoincluding a conventional work-rest 22 on which there is mounted the worksupporting blade 24. The blade 24 is adapted to support a workpiece inthe grinding throat with its axis extendin generally longitudinally. Thework-rest 22 is shown as being rigidly mounted on a slide or saddle 26which is movable on a way 28 which, in turn, is pivotally supported onthe grinding machine bed, not shown. Thus, adjustment of the position ofthe upper edge of the work supporting blade in the grinding throat maybe accomplished by suitably adjusting the positions of the slide orsaddle 26 and the way 28. The constructions of the work supporting bladeand the support means therefor, while subject to wide variation withinthe scope of the invention, are preferably as shown. With suchconstructions, both the loading and unloading apparatus 12 and 14 may beconveniently supported for movement with the work supporting blade andit is preferred practice to so support the said apparatus for reasonswhich will become apparent hereinbelow.

The loading apparatus included in the front section 12 of the grindingmachine operates automatically to feed workpieces in succession to thegrinding throat between the grinding and regulating wheels 18 and 20 fora through-feed grinding operation. Included in the loading apparatus isa hopper 30 which is adapted to hold a number of workpieces in stackedparallel relationship with their axes extending generallylongitudinally. Associated with the hopper 30 is an agitator 32 which isoperable to prevent bridging and/r interlocking of the workpieces in thelower portion of said hopper and to insure that the workpieces may fallfreely through a longitudinal discharge slot 34 provided at the bottomof the hopper (FIG. Disposed beneath the slot 34 in the hopper is areceiver comprising a fluted cylinder or drum 36 which is rotated orindexed intermittently to accept workpieces one at a time from thehopper discharge slot and to deposit workpieces one at a time in adelivery channel 38. The delivery channel 38 extends longitudinally frombeneath the receiver cylinder 36 to the front or receiving end of thegrinding throat defined between the regulating and grinding wheels 18and 20. Located in the delivery channel 38 is a longitudinallyreciprocable delivery rod 40 (FIG. 4) which is power operated tointermittently thrust workpieces along the delivery channel toward therear of the grinding machine and into said front or receiving end of thegrinding throat.

erably supported for movement with the work supporting blade 24. Withthe work-rest and slide constructions shown, the loading apparatus maybe conveniently so supported by providing a rigid connection between theapparatus and the work-rest 22 and/or the slide 26. Such a rigidconnection is provided in the embodiment of the invention shown betweena base 42 of the loading apparatus and the work-rest by means ofsuitable screws and dowels not shown. T he base 42 of the loadingaparatus, as will now be described, supports all of the parts of saidapparatus.

Provided on the base 42 is a longitudinally extending dovetailed way 44which guides and supports a longitudinal slide 46. Suitable binderscrews, not shown, are provided for fixing the longitudinal position ofthe slide 46 relative to the base 42. Mounted on said slide is alaterally or transversely movable supporting plate 48 for the loadingapparatus. As best illustrated in FIG. 6, the supporting plate 48 issecured to the slide 46 by suitable binder screws 50 which extendthrough laterally elongated slots 52 in said plate. A handwheel foradjusting the lateral position of the supporting plate 48 is shown at54. As will become apparent below, all of the parts of the loadingapparatus are suported by and are movable with the supporting plate 48.Thus, the position of the loading apparatus may be adjusted with thework-rest 22 and slide 26 and independently of said work-rest and slidein both lateral and longitudinal directions in a horizontal plane.

As best illustrated in FIG. 6, the delivery channel 38 is preferablyV-shaped in cross-section and is formed in the upper portion of alongitudinaly extending bar 56. The bar 56 extends rearwardly in thegrinding machine so that the discharge end of the channel 38 formedtherein is located adjacent the front or receiving end of the grindingthroat. Located at the rear end of the bar 56 is a guide 58, bestillustrated in FIG. 3. The said guide is provided with a suitableopening 60 through which the workpieces pass as they are delivered tothe grinding throat from the channel 38 in the bar 56. In passingthrough the guide opening 60, the workpieces are confined to a selectedentry path and are properly entered in the grinding throat and supportedon the work supporting blade 24. A shield 62 secured to the guide 58prevents cooling fluid and grinding wheel particles and the like fromescaping forwardly and upwardly from the grinding throat toward themachine operator and the loading apparatus.

In accordance with the presently preferred practice,

the bar 56 in which the delivery channel 38 is defined is adjustablysupported by the laterally movable supporting plate 48. As bestillustrated in FIG. 6, an upright longitudinally extending plate 64carries the bar 56 and said plate is secured for vertical adjustment toan L-shaped longitudinally extending frame member 66. The member 66 ismounted on and secured to the supporting plate 48 as by suitablewelding. In FIG. 2, three binder screws 68, 68 for connecting the plate64 to the frame member 66 are shown located in vertically extended slots70, 70 formed in the said plate. Two vertical adjustment screws 72, 72have their heads in engagement with the supporting plate 48 and arethreaded into the upright plate 64 which carries the delivery bar 56.Connection of the plate 64 with the delivery bar 56 is effected by meansof two binder screws 74, 74, the said screws being entered in suitablethreaded openings in said delivery bar and extend through longitudinallyelongated slots 76, 76 formed in the said plate 64.

It will be apparent that the position of the bar 56 and thus theposition of the delivery channel 38 may be adjusted both vertically andlongitudinally independently of and relative to the supporting plate 48.The vertical and longitudinal adjustments of the delivery bar 56 whichmay be effected respectively by movement of the upright plate 64relative to the supporting plate 48 and movement of the delivery barrelative to said upright plate and supporting plate are utilized foraccurately positioning the discharge end of the delivery channel 38relative to the grinding throat and the upper edge of the worksupporting blade 24 after appropriate lateral and longitudinaladjustments of the loading apparatus position have been accomplished atthe slide 46 and supporting plate 48. -It will be apparent that when allof the required adjustments have been accomplished, the loadingapparatus will be moved with the work-rest 22 and the work supportingblade 24 and the desired position of the discharge end of the deliverychannel 38 relative to the grinding throat and the upper edge of thesaid blade will be maintained during operation of the machine.

Referring now particularly to FIG. 4, it will be observed that theafore-mentioned reciprocahle delivery rod 40 which intermittentlythrusts workpieces along the delivery channel 38 into the grindingthroat is supported and guided in said channel by the delivery bar 56and by a bracket 78. The bracket 78 is rigidly secured to and extendsupwardly from the frame member 66, connection of the bracket with thesaid member being accomplished by two bolts '80, '80 (FIG. 2).

As previously mentioned, the delivery rod 40 is power operated and Whileany usual or preferred operating means for the rod may be utilized, thepresently preferred means comprises a conventional air cylinder 82. Theair cylinder 82 is supported by suitable brackets 84 and 86 mounted onthe L-shaped frame member 66 and in cludes a pneumatically operatedpiston 88 and a piston rod 90 which is connected for movement with thepiston 88 and which projects through the front end of the cylinder. Asuitable laterally extending connecting link 92 is utilized forattaching the projecting end of the piston rod 90 to the delivery rod40. The said link may be secured to the delivery rod 40 at selectedlongitudinal positions by means of a bolt 93 adapted to extend through asuitable opening in said link and through one of a longitudinal seriesof openings 95, 95 in said rod. A longitudinally extending rod 96 isalso attached to the projecting or front end of the piston rod 90 bymeans of a suitable connecting link 94. The rod 96 has first and secondcontact buttons 98 and 100 fixedly mounted thereon at opposite ends andsaid rod is supported and guided for longitudinal movement by a bracket102. The bracket 102 is rigidly secured to an upright plate 104 whichextends longitudinally adjacent the air cylinder 82 and which is securedalong its lower edge to the supporting plate 48 as by suitable welding.Rigidly mounted on the bracket 102 are first and second limit switches106 and 108 which are adapted to be actuated respectively by the contactbutton 98 and the contact button 100.

In Fig. 4 the delivery rod 40 is shown in the position it occupies atthe end of a delivery stroke thereof. In such position, the rod deliversa workpiece to the guide 60 and to the grinding throat between thegrinding and regulating wheels 18 and 20', the said workpiece being atleast partially entered in the grinding throat by the rod so that it maybe drawn therethrough by the grinding and regulating wheels in the usualmanner for a through-feed grinding operation. It will be observed thatfeed strokes of the rod 40 are effected by retraction of the piston rod90 into the air cylinder 82 and that return strokes of the said rod areeffected by forward or advancing movements of the saidpiston rod.Exemplary control means for regulating the reciprocable movement of thepiston rod 90 and thus the reciprocable movement of the delivery rod 41)are described hereinafter. It will also be observed in FIG. 4 that thelimit switch 1113 is actuated by the contact button 100 at the end ofeach feed stroke of the delivery rod 411 and that the limit switch 106is actuated by the contact button 98 at the end of each return stroke ofsaid delivery rod. It is to be understood that the arrangement of thelimit switches 1116 and 108 and the actuating means therefor is subjectto Wide variation, the arrangements shown and described being exemplary.

As best illustrated in FIGS. 3 and 4, the aforementioned fluted cylinder36 which accepts workpieces from the hopper 3i and deposits the same oneat a time in the delivery channel 38 has its axis extending generallylongitudinally and is disposed within a suitable housing 110. Thehousing 110 is supported above the delivery channel 38 and beneath thehopper 30 by two similar upright bars 112, 112. The bars 112, 112 havetheir lower ends secured to the supporting plate 48 and are connected tosaid housing at opposite ends thereof as by suitable welding. Alsosecured to the housing 110 are two horizontally extending connectingbars 114, 114 which are rigidly connected to and which extend generallyhorizontally and laterally from the upright plate 104 at its upper edge.An end plug 116 at the rear end of the cylinder housing 110 is providedwith a central opening 118 in which there is disposed a bushing 120which receives the rear end of a spindle 122 formed integrally on thecylinder 36. At the forward end of the housing 110 there is provided acap 124 which also has a central opening 126. The opening 126 is linedwith a bushing 128 which receives the opposite end of the spindle 122.In a lower portion of the housing 110, there is provided alongitudinally extending slot 130 which is disposed above the deliverychannel 38 and through which workpieces may fall freely by gravity tosaid channel. A similar longitudinally extended slot 132 is provided inan upper portion of the cylinder 11d beneath the discharge slot 34 inthe hopper 30. Workpieces are entered in the flutes of the cylinder 36from the hopper discharge slot 34 through the housing slot 132 andaccordingly said slot 132 may be hereinafter referred to as a receivingslot. Similarly, workpieces are discharged from the flutes of thecylinder 36 through the lower slot 130 and said slot may be hereafterreferred to as a discharge slot. Secured to the housing 110 adjacent thedischarge slot 131 is a shield or guard 134 which insures thatworkpieces discharged through the said slot are directed into thedelivery channel 38,

As shown, the cylinder 36 includes six equally spaced longitudinallyextending flutes 1315, 136 in which workpieces may be held, the numberof flutes, however, being subject to variation. Preferably several suchcylinders are provided and they are adapted to be used interchangeablyfor handling elongated workpieces of different sizes and shapes. Inoperation of the loading apparatus, the cylinder 36 is intermittentlyrotated or indexed through a selected angle so that one of the flutes136, 136 regis- 6 ters with the receiving slot 132 in the housing to at;low a workpiece to be entered in said flute while a diametricallyopposite flute 136 registers with the discharge slot to discharge aworkpiece to the delivery channel 38. When there are six equally spacedflutes provided in the cylinder 36, the indexing angle is of course 60.

The operating means for intermittently rotating or indexing the flutedcylinder 36 through a selected angle may vary widely within the scope ofthe invention. In accordance with the presently preferred practice,thecylinder 36 is connected with a ratchet wheel 133 (FIG. 6); A pawl 140operated by a conventional air cylinder rotates the said ratchet wheeland the fluted cylinder 36 as required. As best illustrated in FIG. 3,the ratchet wheel 138 is mounted on the front portion of the spindle 122adjacent the front end of the cylinder 36 and within the cylinderhousing 110. The ratchet wheel 138 is secured against rotation relativeto the spindle 122 by a suitable key 144 and is secured against axialmovement relative to said spindle by a nut 146 which engages a threadedportion of the spindle forwardly of said ratchet wheel. The pawl 140 ispivotally mounted on a slide 148 which is connected to and reciprocatedby a piston rod 150 of the air cylinder 142. Asuitable leaf spring whichis secured at one end to the slide 148 has its other end in engagementwith the pawl 140 to bias said pawl into engagement with the ratchetwheel 138.

The air cylinder 142 which constitutes the operating means for the pawl140- is supported by a bracket 154 which is mounted on a platform 156secured to the upright plate 104. Also secured to the plate 104 is abracket 158 which has formed at its upper surface a way 160 on which theslide 148 is reciprocated at the urging of the air cylinder piston rod150. A limit switch 162, best illustrated in FIGS. 1 and 2, is alsosupported on the upright plate 164 by a suitable bracket and is actuatedby a contact button 164 which is carried by the slide 148. The saidlimit switch 162 is arranged so as to be actuated by the contact button164 when the air cylinder 142 is operated to actuate the pawl 141) andto thereby rotate or index the cylinder 36. More specifically, theswitch 162 is actuated at the completion of an indexing movement of thecylinder 36. I

In accordance with presently preferred practice, a brake means isprovided for preventing overtravel of the cylinder 36 when it isindexed. As shown, the said brake means comprises a disc of a suitablebrake material such as cork which is rigidly secured to the front faceof the nut 146 within the cylinder housing 110 and which is in axialengagement with the housing end cap 124. As best illustrated in FIG. 3,the housing end cap 124 is biased into engagement with the disc 166 by aplurality of small coil springs 168, 168 (one shown). The springs 168,163 respectively embrace a plurality of screws 170, 170 which extendthrough suitable openings in the end cap 124 and which are entered insuitably threaded openings in the front end of the cylinder housing 110.It will be apparent that by suitably turning the screws 170, 170, thebiasing force of the springs 168, 168 on the end cap 124 and thus thebraking effectiveness of the disc 166 may be adjusted as desired. I

The afore-mentioned hopper 30 which holds a stacked supply of workpieceswith their axes in parallel relationship and extending generallylongitudinally is preferably generally V-shaped in cross-section as bestillustrated in FIG. 5. The said hopper is supported with the dischargeslot 34 in its lower portion above the receiving slot 132 in thecylinder housing 111 by means of a first upright bar 172 secured at itslower end to the supporting plate 48 and a second upright bar 174secured to the upright plate 104. In order that workpieces of diiferentlengths and shapes may be accomplished, the hopper 30 is preferablyprovided with a longitudinally adjustable transverse partition 176 asbest illustrated in FIG. 3. Connected to a lower portion of theadjustable partition 176 and extend- 7 ing through a suitably threadedopening 178 in the front wall of the hopper 30 is a threaded adjustingrod 180. A binder nut 181 is threaded on the rod 180 outwardly orforwardly of said front wall of the hopper 30 to secure the lowerportion of the partition 176 in a selected longitudinal position. Theupper portion of the partition 176 has wings or flanges 182, 132 formedthereon at opposite sides and a longitudinal series of notches 134, 134is provided at the upper portion of each side wall of the hopper 30. Thesaid upper portion of the hopper may be secured in a selectedlongitudinal position by entering the wings or flanges 182, 182 in theappropriate notches 184, 134. FIGS. 2 and 5 best illustrate theconnection of the partition 176 with the upper portion of the hopper 30.

In preferred form, the agitator 32 which prevents bridging andinterlocking of workpieces in the hopper 30 comprises a pivotallysupported longitudinal agitating or lifting member 186 disposed withinthe hopper 30 as best illustrated in FIG. 5. A shaft 138 which has itsends journaled in the opposite end walls of said hopper supports themember 186 for pivotal movement toward and away from the center of thehopper. The member 186 has upper and lower spaced apart longitudinallifting ribs or flanges 190 and 192 formed thereon and also has a smoothcurved surface disposed between said ribs or flanges. The lip of thelower rib 192 is disposed closely adjacent the upper portion of thehousing 110 of the cylinder 36 so that workpieces are prevented frompassing between said housing and member when they are discharged fromthe hopper slot 34. A longitudinal partition 194 within the hopper 30confines the workpieces to the zone adjacent the lifting ribs or flanges190 and 192.

In operation of the loading apparatus, the agitating appease member 186is intermittently actuated so as to be pivoted about the shaft 188 inthe clockwise direction as viewed from the front of the grindingmachine. When the member is so actuated, the ribs 190 and 192 thereontend to lift the workpieces and to effect relative movementtherebetween. This results in the destruction of any natural bridgeswhich may have been formed by the workpieces and disengagement ofinterlocked workpieces whereupon, the said workpieces are free to fallby gravity into the receiving slot 132 in the housing 110 and be enteredin the flutes 136 in the cylinder 36. The operating means forintermittently pivoting the agitating or lifting member 186 is shown ascomprising an air cylinder 196 which is supported by a bracket 198rigidly connected to the upright plate 104 but it is to be understoodthat other operating means may be utilized within the scope of theinvention.

From the foregoing it will be apparent that the loading apparatus of thegrinding machine may be operated automatically to deliver workpieces tothe grinding throat of the machine at appropriate intervals. It will befurther apparent that the said apparatus may be readily adapted toaccommodate workpieces of various shapes and sizes. When elongatedworkpieces having uniform diameters are to be ground, the apparatus maybe used to feed workpieces for a conventional through-feed grindingoperation. In such a grinding operation, workpieces are delivered insuccession at suitable intervals to the grinding tln'oat between thegrinding and regulating wheels and the workpieces are successively drawnlongitudinally through the grinding throat by said wheels and aredeposited at the discharge end of the throat on a suitable conveyor orthe like, not shown. When, on the other hand, workpieces havingnon-uniform diameters throughout their lengths are to be ground, they ofcourse cannot be permitted to pass completely through the grindingthroat as in a conventional through feed grinding operation. In suchevent the unloading apparatus constiuting the rear section 14 of thegrinding machine is utilized and is operated automatically in accordancewith the improved through-feed grind- ,ing method of the presentinvention to lift or pivot the workpieces upwardly out of the grindingthroat when they have advanced to a preselected position therein. Thesaid improved grinding method and the unloading apparatus will bedescribed with reference to the exemplary nonuniform workpieceillustrated in the drawings, i.e., a conventional twist drill W.

As best illustrated in FIG. 7, a conventional twist drill W has astraight shank and a gradually tapering drill portion which is of agreater diameter at its tip end than at its shank end. In accordancewith the improved throughfeed method of grinding workpieces such as thedrill W to a non-uniform diameter throughout their length, the grindingand regulating wheels of the grinding machine are dressed to provide forminimum grinding throat width and minimum diameter of the finishedworkpiece adjacent the discharge end of the throat. The remainingportion of the grinding throat is shaped, by suitably dressing the saidwheels, to provide for a taper as shown in FIG. 7, or to provide forother workpiece contours of larger diameter than the diameter of saidthroat portion adjacent the discharge end of the throat. The workpieces,such as the drills W, are fed into the grinding throat from the endopposite the discharge end as in a conventional through-feed operationand are advanced into the throat until they reach a selected position inthe throat wherein a selected portion thereof (the shank of the drill Win FIG. 7) has been ground to the minimum diameter, the remainingportion thereof (drill portion of the twist drill W in FIG. 7) beingconcurrently ground to a desired taper or other contour of largerdiameter. When the drills or other workpieces have reached the saidselected position in the grinding throat, their longitudinal movementthrough the said throat is interrupted and they are removed upwardlyfrom the throat with their diametral surfaces ground non-uniformlythroughout their lengths as required.

It will be observed in FIG. 7 that the grinding and regulating wheels 18and 20 are dressed so that a portion of the shank of a twist drill Wprojects from the discharge end of the grinding throat when the drillhas reached the selected position in the throat wherein its shank anddrill portion are ground as required. While the method of the presentinvention is not to be construed as being so limited, it is thepresently preferred practice .to provide for such projection of the endportion of the drill or other workpiece from the grinding throat. Aswill become apparent herinbelow, the upward removal of the drill orworkpiece from the grinding throat is facilitated when its end portionprojects from the throat discharge end.

An unloading apparatus adapted for operation in accordance with theimproved method of the invention may take a variety of forms. Apparatusmay be provided, for example, to effect a hammer-like blow on the end ofthe drill W or other workpiece which projects from the discharge end ofthe grinding throat whereby to pivot the said drill or other workpieceabout the corner of the work supporting blade and thus remove the samefrom the grinding throat in an upward direction. Still other apparatusfor implementing the method of the present invention may comprise meansfor grasping the projecting end of the drill or other workpiece andlifting the said drill or workpiece upwardly and out of the grindingthroat with its axis remaining substantially longitudinal.

The unloading apparatus construction which is presently preferred andwhich is illustrated in the drawings includes a means whereby anon-uniform workpiece such as a twist drill is removed upwardly from thegrinding throat in a pivotal movement when the workpiece reaches aselected position in said throat. The said means comprises generally anunloading turret or wheel 200 which is provided with a plurality ofradial bores 202, 202, each adapted to receive the projecting end of adrill W. The unloading turret or wheel 20 is indexed or rotated througha selected angle intermittently so that the radial bores 202, 202 moveupwardly into register with the discharge end of the grinding throat insuccession. The pro- '9' jecting ends of the drills W are entered in thebores 202, 202 in succession as the drills reach the aforesaid selectedposition in the grinding throat and are moved upwardly and away from thesaid throat discharge end in an arc lying in a substantially verticalplane whereby the said drills are lifted upwardly from the grindingthroat in a pivotal movement. When the drills are pivoted to a selectedposition, they fall by gravity from the radial bores 202, 202 into areceiving chute 203. In order that the unloading wheel 200 may beindexed at the proper instant to lift the drills out of the grindingthroat when they reach the said selected position, there is provided acontrol means which is operable responsive to drill position to cause anoperating means for the unloading wheel to index the same.

As previously mentioned, the unloading apparatus of the grinding machineis preferably supported for movement with the work-rest 22 and the slideor saddle 26 whereby the said apparatus will be moved with the worksupporting blade 24. As best illustrated in FIG. 2, a base 204 of theunloading apparatus is rigidly secured to the slide or saddle of thegrinding machine as by suitable welding. Mounted on the base 204 is alongiutdinally adjustable supoprting block 206. The said supportingblock is secured in position by suitable binder bolts 208 which extendthrough longitudinally extended slots 210 formed in the base 204 and thesupporting block may be conveniently moved longitudinally by a suitablehandscrew 212. Supported on the block 206 for lateral movement is agenerally L-shaped bracket 214. The said bracket is secured to thesupporting block 206 by the binder bolts 208, 208 which extend throughlaterally extended slots 216 formed in the bracket. The lateral positionof the bracket 214 may be conveniently adjusted by a handscrew 218. Thebracket 214 supports a platform 220 for vertical movement relativethereto and the said platform has the aforementioned unloading wheel 200and its operating means mounted thereon. A pair of binder bolts 222, 222secure the platform 220 to the bracket 214 and extend through verticallyextended slots 224, 224 formed in said bracket. Vertical adjustment ofthe position of the platform 220 may be conveniently accomplished bymeans of a suitable handscrew 226 and indication of the verticalposition of the said platform relative to said bracket is provided by asuitably calibrated scale 228.

From the foregoing it will be apparent that a desired position of theunloading wheel 200' and its drill receiving bores 202, 202 relative tothe discharge end of the grinding throat may be established by effectingsuitable adjustments of the positions of the supporting block 206, thebracket 214, and the platform 220. Once established, the desiredrelationship between said wheel and said throat discharge end will bemaintained irrespective of movement of the work supporting blade 24.

As best illustrated in FIGS. 8 and 10, in the preferred construction ofthe apparatus the unloading wheel 200 is provided with six radial bores202, 202 and is fixedly supported on a stub shaft 230 for rotationtherewith by means of a key 232 and a not 234. The stub shaft 230extends horizontally and laterally of the grinding machine and isrotatably supported in bushings 236, 236 disposed in a suitable openingin a bearing block 238. The bearing block 238 is disposed within ahousing 240 and is supported on a mounting plate 242 which is secured tothe platform 220 which supports the unloading apparatus. The shaft 230projects through the side of the housing 240and the unloading wheel 200is mounted on the projecting end of the said shaft.

The control means which is operable responsive to the position of thedrills W may take various forms within the scope of the invention. Inits presently preferred form, the said means comprises a highlysensitive switch which is indicated generally at 244 and which isactuated by the projecting end of a drill within a bore 202 to completean electrical circuit to ground. A switch armature 24d disposed withinthe housing 240 is provided with a contact button 248 at one end thereofand is connected at its opposite end to a pivotally supported lever 250.The lever 250 is supported intermediate its ends by a pivot pin 252carried by the bearing block 238 and at the end of said lever 250opposite the armature 246 there is provided a drill engaging pin 254.The pin 254 extends laterally from the lever 250 through the side of thehousing 240 and into an annular groove 256 formed in the face of theunloading wheel 200. The said annular groove 256 com municates with theinner ends of the bores 202, 202 in the wheel 200 and the free end ofthe pin 254 is disposed in said groove so as to project into the innerend portion of each of the bores 202, 202 and thus into the path of adrill when the bores are in registry with the discharge end of thegrinding throat. Thus, when a drill enters a bore 202 from the grindingthroat the projecting end of the drill engages the pin 254 and causesthe lever 250 to be pivoted about the pin 252. Since the distance fromthe contact button 248 at the end of the switch armature 246 to thepivot pin 252 is substantially greater than the distance from said pin252 to the work engaging pin 254, only a very slight movement of the pin254 is required to provide a substantial movement of the contact button248.

When the contact button 248 is moved as described by engagement of theend of a drill with the pin 254, the said button engages a secondcontact button 258 and grounds a conductor 260 which is connected to thesaid button 258 within a terminal block 262 mounted on the housing 240.

As will be described more fully hereinbelow, grounding of the conductor260 results in actuation of the operating means for the unloading wheel200 whereupon the said wheel is indexed or rotated through a selectedangle to lift or pivot a drill W upwardly from the grinding throat andto move a succeeding bore 202 into registry with the discharge end ofsaid throat.

The operating means for intermittently indexing the unloading wheel 200preferably comprises a pawl and indexing wheel device 264 which isoperated by a conventional air cylinder 266. As best illustrated in FIG.8, there is formed integrally on the stub shaft 230 at the end oppositethe unloading wheel 200 an indexing wheel 268. The indexing wheel 268carries a plurality of pins 270 which are arranged in an annular seriesand which project axially from the radial surface of said wheel. Whenthe unloading wheel 200 is provided with six radial bores, as shown, thewheel 268 is provided with a like number of pins 270. The pins 270 areadapted to be engaged by a pawl 272 which is pivotally supported at theprojecting end of a piston rod 274 of the air cylinder 266. Also carriedon the projecting end portion of the piston rod 274 is a mounting block276 which in turn carries a biasing spring 278. The spring 278 maintainsthe pawl 272 in engagement with the radial surface of the wheel 268 fromwhich the pins 27 0 project.

The operating means for the unloading wheel 200 preferably also includesa locking device 280 which is adapted to establish the indexed positionsof the wheel 200 with a high degree of accuracy and to lock the saidwheel in each of said positions between indexing movements thereof. Asshown, the said device comprises a pivotally supported latch 282 whichis adapted to be moved into and out of locking engagement with the Wheel268 in timed relation with the indexing movements of the wheel. Formedat the periphery of the wheel 268 are six locking notches 284, 284. Saidnotches are spaced to correspond with the six index positions of saidwheel and of the unloading wheel 200. The latch 282 is entered in thenotches 284 in sequence and when so entered, the said latch accuratelyestablishes the indexed position of the wheel 268 and thus the indexedposition of the unloading wheel 200 so that a radial bore 202 of thelatter may receive the projecting end of a drill W. During indexingmovements of the wheels 268 and 200, the latch 282 is pivotally re- 1 1tracted from locking engagement with the notches 284, 284 by the nextdescribed means.

A pivotally supported notched member 286 (FIG. 9) 'which is carried bythe mounting block 27 6 on the projecting end of the piston rod 274moves the latch 282 into and out of engagement with the notches 284 inthe wheel 268. An ear 288 formed on the latch 282 is entered in thenotch of the member 286 and is engaged by the edges of said notch topivot the said latch as the member 286 is moved with the said mountingblock. That is, when the air cylinder 266 is operated to index the Wheel200, the notched member 286 is moved toward the axis of the wheels 200and 268 by the mounting block 276 and engages the car 288 so as to pivotthe latch 282 out of engagement with the index wheel notches 284, 284against the bias of a leaf spring 290. The pawl 272 then engages one ofthe pins 27 on the indexing wheel and rotates the said wheel and theunloading wheel 200 toward the next succeeding index position. Duringsaid indexing movement of the pawl 272, the ear 288 of the latch 282 isurged out of the notch of the member 286 by the rear or trailing edge ofsaid notch and said ear slides along the face of the member 286 and thenoil the curved rear or trailing edge 292 of said face (FIG. 9). Whenthis occurs, the biasing spring 290 causes the latch 282 to engage theradial face of the index wheel 268 between the notches 284, 284. As theindexing movement of the pawl 276 and the wheel 268 continues, the latch282 is maintained in engagement with said radial face of the Wheel 268under the bias of the spring 290 until a locking notch 284 is rotatednearly into registry with the said latch. When a notch 284 is sopositioned, relative to the latch 282, the said latch enters a receivinggroove 294 which extends forwardly from the leading edge of said notchand further rotation of the index wheel causes the trailing edge of saidnotch to engaage the adjacent edge portion of the latch whereupon thesaid latch enters the notch with a snap movement under the bias of thespring 290. Thus a positive stop for the indexing movement of the wheel268 is provided, the angle through which the wheels 280 and 268 arerotated is accurately determined, and the indexed position of the saidwheels is accurately established. During the return movement of thepiston rod 274, the car 288 of the latch '282 engages the curvedtrailing edge 292 of the said memher 286 whereby to momentarily pivotthe said member upwardly against the bias of a spring 296 and re-enterthe notch of the said member.

In addition to the above-described parts thereof, the unloadingapparatus preferably includes first and second 'limit switches 298 and300 (FIG. 2). The first limit switch 298 is adapted to be actuated by acontact button 302 when the piston rod 274 of the air cylinder 266completes an indexing stroke and the second limit switch 300 is adaptedto be actuated by a contact button 304 when the said piston rodcompletes a return stroke. The limit switch 298 is supported on arearwardly extending portion of the housing 240 of the unloadingapparatus and the limit switch 300 is supported on a suitable bracket306 which is secured to and extends upwardly from the platform 220. Thecontact buttons 302 and 304 are adjustably connected with the piston rod274 for movement therewith by means of supporting rod 308, a yoke 310and button carrying member 312.

From the foregoing description of the grinding machine, it will beapparent that the said machine can be set up for automatic operationwherein one cycle of operation will complete the grinding of oneworkpiece. vAs will become apparent, production operation requires anoperator only for the purpose of starting and stopping the machine atthe control panel 16 whether the workpieces to be ground are of uniformor non-uniform diameter throughout their lengths.

dinally through the grinding throat of the machine in a conventionalthrough-feed operation and may be collected at the discharge end of saidthroat on a suitable conveyor or in a suitable receptacle. In setting upfor such automatic operation, the grinding and regulating wheels aredressed and their positions are adjusted as required, a selectorcylinder 36 having flutes of a suitable size for receiving theworkpieces is incorporated in the loading apparatus, and the workpiecesare deposited in the hopper 30 with the position of the hopper partition176 suitably adjusted. Appropriate adjustments are made at variouspoints in the loading apparatus to position the discharge end of thedelivery channel 38 in registry with the receiving end of the grindingthroat whereupon the machine is conditioned for automatic operation.

When workpieces having non-uniform diameters throughout their length,such as the twist drill W, are to be ground, the grinding and regulatingwheel surfaces are dressed as described above and their positions areadjusted as required. The loading apparatus is set up as described aboveand the unloading apparatus is incorporated in the machine. Suitableadjustments are effected in the unloading apparatus to position theunloading wheel bores in proper relation to the discharge end of thegrinding throat and the machine is then conditioned for automaticoperation.

Obviously, the means for controlling the automatic operation of thegrinding machine may take a variety of forms. The control means forautomatically operable mechanisms and devices such as wheel dresserswhich may be included in the grinding and regulating wheel sec tion 10of the machine as well as control means for the grinding and regulatingwheel operating means may be conventional and illustration anddescription of such means is not deemed essential for a fullunderstanding of the invention. On the other hand, it is believed thatdescription of exemplary means for controlling the automatic operationof the loading and unloading apparatus of the grinding machine, althoughsaid means may be partly conventional, will contribute to a fullunderstanding of the features and operation of said apparatus.

As previously mentioned, conventional air cylinders are preferablyutilized throughout the loading and unloading aparatus of the grindingmachine as operating means for the various power driven mechanisms anddevices of said apparatus. In further accord with conventional practice,each of the said air cylinders is preferably provided with atwo-position solenoid operated control valve for selectively introducingpressurized air to opposite sides of the cylinder pistons and forselectively venting or exhausting the air chambers on opposite sides ofthe cylinder pistons whereby to impart the required intermittentreciprocable motion to said cylinder pistons and their respective pistonrods. Such control valves are well known and it is deemed unnecessaryfor the purposes of the invention to show and describe their detailedconstruction. The manner in which the operation of the said valves iscontrolled by an exemplary first solenoid 314 moves the said controlvalve to one position wherein it causes the piston and piston rod of theair cylinder 82 to be moved so as to drive the delivery rod 40rearwardly in the grinding machine for delivery of a workpiece to themachines grinding throat. There is no spring return provision in thesaid solenoid 314 or the control valve for the air cylinder 82. Thus,momentary energization of the solenoid 314 will result ascents l3 incommencement of a feed stroke of the delivery rod 40 and if the solenoid3-14 is thereafter dc-energized, the control valve will remain in itssaid one position and the feed stroke of the rod. 40 will be completed.Movement of the control valve for the air cylinder 82 to its otherposition wherein the said cylinder is caused to retract the delivery rod40 is accomplished by energization of the second solenoid 316. Operationof the cylinder 82 responsive to energization of the solenoid 316 issimilar to that which occurs when the solenoid 314 isenergiZed. That is,momentary energization of the solenoid 316 results in commencement of areturn stroke of the delivery rod 40 and subsequent de-energiza. tion ofsaid solenoid will not terminate the said stroke,

there being no spring return provision in the solenoid or the controlvalve for the air cylinder.

The control valves for the air cylinders. 196 and 142 which respectivelyactuate the workpiece agitating memher 186 and the pawl and ratchetwheel device which indexes the fluted receiver cylinder 36 are movedsimultaneously from one position to the other by a third solenoidindicated at 318 in FIG. 11. the solenoid 318 simultaneously moves thesaid two control valves to positions wherein they respectively cause theair cylinders 19 6 and 142 to actuate the agitating member 186 and toindex the receiver cylinder 36. The solenoid 318 is of the spring returntype and, thus, when the said solenoid is de-energized, the said twocontrol valves are simultaneously moved to their other positions whereinthey respectively cause the piston rods of the air cylinders 196 and 142to be retracted for succeeding workpiece agitating and cylinder indexingmovements.

The position of the control valve for the air cylinder 266 whichactuates the pawl 272 whereby to index the unloading wheel 200 isregulated by a fourth solenoid which is designated by the referencenumeral 320 in FIG. 11. When the solenoid 320 is energized, it adjuststhe position of the said control valve so that the air cylinder 266 isoperated to index the unloading wheel 200 and when the said solenoid isdc-energized, a spring return provision causes the control valve tooperate the air cylinder 266 so that its piston and piston rod areretracted for a succeeding indexing movement or stroke.

The manner in which the above-mentioned solenoids are energized andde-energized and the manner in which the automatic operation of thegrinding machine is regulated and controlled by the electrical controlsystem of FIG. 11 will now be'described, it being understood that manyspecifically difierent electrical control systems can be provided withinthe scope of the invention. It; will be observed that all of theelectrical control elements of the system are supplied with energy fromtwo lead lines L1 and L2 which may be connected with a conventionalsource. A normally closed switch is located in the lead line L1 andcomprises an emergency stop switch which when opened will dc-energizethe entire electrical system. Also located in the lead line L1 is aconnector 324 and located in the lead line L2 is a similar connector326. The portion of the electrical system which appears below theconnectors 324 and 326 in the wiring diagram of FIG. 11 is utilized onlyin controlling the operation of the unloading apparatus of the grindingmachine and may be disconnected from the rest of the system when thesaid apparatus is not utilized as in the grinding of workpieces havinguniform diameters. The electrical control system will first beconsidered as it relates to the control of the grinding machine ingrinding operations on uniform workpieces and accordingly the portion ofthe system below the connectors 324 and 326 may be ignored for thepresent.

With the grinding machine set-up as described above for the automaticgrinding of uniform workpieces, the machine operator may initiateautomatic operation of the machine by pressing a push button on thecontrol panel 16 which closes a switch 328 in circuit with the Whenenergized solenoid 314. The switch 328 is of the type which isspringbiased toward its open position and it therefore opens the circuit'de-energizing the solenoid 314 when the push button is released by theoperator. Since there is, however, no spring return provision in thesolenoid 314 or in the control valve which it operates, the momentaryenergization of said solenoid will result in movement of the controlvalve to a position wherein it causes the air cylinder 82 to initiate aself-sustaining feed stroke of the delivery rod '40 as described above.

In addition to the switch 328, there is also associated with theaforesaid control panel push button a switch 330 which is connected inparallel with the switch 328 and in circuit with the solenoid 314. Theswitch 330 is connected with the control panel push button so as to beoperated by said button selectively. That is, a connection is providedbetween the said button and switch which permits the machine operator toclose the switch 330 by pressing said button or to press said buttonWithout affecting the position of said switch at his option. As will beexplained more fully hereinbelow, the electrical system is conditionedto control the automatic operation of the grinding machine when theswitch 330 is closed by depression of the control panel push button.When the posit-ion of the switch 330 is unaffected by depression of thesaid button, the grinding machine will complete one cycle of operationand will then stop automatically as will also be explained. Descriptionof the detailed construction of the switches 328 and 330 and connecitngmeans between said switches and the control panel push button is deemedunnecessary for an understanding of the invention, as switching devicesadapted to be operated as described are well known. For example, oneconventional switching device suitable for the purposes of the inventioncomprises a push button which is rotatable to two discreet positions andwhich is connected with first and second switches so that it momentarilycloses the first switch (such as 328) and permanently closes the secondswitch (such as 330) when depressed in one rotated position and so thatit momentarily closes the first switch (328), but does not atfect theposition of the second switch (330) when depressed in its other rotatedposition.

Irrespective of the position of the switch 330, the feed stroke of thedelivery rod 40 initiated by the momentary energization of the solenoid3 14 upon closing of the switch 328 will continue until the workpiecehas been properly entered in the grinding throat for the reasons givenabove. When the feed stroke is completed, the limit switch 108 will beclosed in circuit with the solenoid 316. Also connected in circuit withsaid solenoid and limit switch is the limit switch 162 which isassociated with the air cylinder 196 which actuates the indexing meansfor the receiver cylinder 36. Said limit switch 162 is normally closedin circuit with the switch 108 and the solenoid 316 and said solenoid istherefore energized upon closing the limit switch 108. When thesolenoi-d 316 is energized, it adjusts the position of the control valvefor the air cylinder 82 so that said cylinder is operated to initiate areturn stroke of the delivery rod 40 as stated above. Connected inparallel with the solenoid 316 is a control relay CR1 which is alsoenergized upon closing of the limit switch 108 and which closes anormally open switch 332 when so energized. The switch 332 shunts thelimit switch 108 and maintains the solenoid 316 in an energizedcondition upon opening of the said limit switch 108 which occurs as thereturn stroke of the delivery rod 40 commences.

It will be recalled that it is unnecessary to maintain energization ofthe solenoid 316 in order to effect a completed return stroke of thedelivery rod 40. The control relay CR1 and the switch 332 operatedthereby are not, however, superfluous. It will be observed that thesolenoid 318 which controls operation of the agitator air cylinder 142and the air cylinder 1% which indexes the of their respective pistonrods. control relay CR1 opens the switch 332 so that subse- 15 receivercylinder 36 is connected in parallel with the solenoid 316 and incircuit with the switch 332. Also connected in parallel with thesolenoid 316 and in circuit "with the switch 332 and the solenoid 318 isthe limit switch 106 actuated by the delivery rod air cylinder 82. .Saidlimit switch 106 is closed in circuit with the switch 36, it will benoted that the said switch is actuated upon termination of the indexingmovement of the piston rod 150 of said air cylinder. When so actuatedthe :limit switch 162 is opened in the circuit which includes thesolenoids 316 and 31S and the control relay CR1. :Resuitingde-energization of the solenoid 316 has no effect on the position of thedelivery rod 40 for the reasons given above, but de-energization of thesolenoid 318 results in the spring return movement of the control valvesfor the cylinders 142 and 196 and in retraction De-energization of thequent closing of the limit switch 162 upon completion of the retractingmovement of the piston rod 150 of the air cylinder 196 cannot result inautomatic re-energization of the solenoids 316 and 318 and said relayCR1.

The limit switch 162 is thus actuated momentarily and when so actuatedduring its momentary actuation, in addition to its operation describedabove, it sets a timer 334 in operation. Said limit switch is connectedin circuit with the timer 334 and is closed to initiate timer operationwhen the air cylinder 196 completes an indexing stroke as described.There is also connected in circuit with the timer 334 and in parallelwith the limit switch 162 a normally open switch 335 and a normallyclosed switch 336. The normally open switch 335 is controlled by thetimer 334 and is closed thereby when the timer is set in operation. Thenormally closed switch 336 is controlled by the control relay CR1 and isclosed when said relay is in a tie-energized condition. Thus, the limitswitch 162 is shunted and the timer 334, having once been set inoperation, will be supplied with power through the switches 335 and 336and will continue to operate until a predetermined period of time haselapsed. At the end of said predetermined time period, the switch 335will be opened by the timer and its operation will be self-terminated.There is also provided in circuit with the timer 334 a control switch337 which when closed energizes the timer for operation by the limitswitch 162 and the switches 335 and 336. When the control switch 337 isopened, the timer 334 is de-energized and has no eifect on the remainingelements of the control system.

During the predetermined time period of operation of the timer 334 andnear the end of said period of operation, the said timer momentarilycloses a normally open switch 338. The switch 338 is connected incircuit with the aforesaid push button actuated switch 330 and incircuit with the solenoid 314 which effects feed strokes of the deliveryrod 40. The time period which elapses between initiation of timeroperation and the momentary closing of the switch 338 is such that thedesired grinding operation It will be apparent, that if the switch 330is closed for automatic operation of the machine, the momentary closingof the switch 338 by the timer 334 will result in energization of thesolenoid 314 and a new cycle of machine -16 operation will be therebyinitiated. If on the other hand the switch 330 is open, single cycleoperation of the machine having been selected, the momentary closing ofthe switch 338 will have no efiect.

When non-uniform workpieces are to be ground in the machine, theelements of the afore-mentioned lower portion of the wiring diagram areutilized and the switch 337 is opened to de-energize the timer 334. Thecontrol panel push button is pressed as described above to set themachine in operation for either a single cycle of operation or a seriesof automatically controlled cyclm of operation. The electrical controlsystem then regulates the operation of the loading apparatus asdescribed above and a workpiece such as a drill W is delivered to thegrinding throat of the machine and advances through said throat untilits end projects beyond the discharge end of said throat and into aradial bore of the unloading wheel 200. When the projecting end of thedrill or other workpiece engages the pin 254 in the radial bore of theunloading wheel 200 so as to pivot the lever 250 and move the switcharmature 246 to close a circuit to ground, the unloading apparatus isset in operation as described hereinbelow.

Completion of a circuit to ground by the armature 246 energizes anelectronic relay 340 and results in closing of a normally open switch342 which is controlled by said relay. The switch 342 is in circuit withthe solenoid 320 which controls the operation of the air cylinder 266which indexes the unloading wheel 200 and said switch is also in circuitwith the limit switch 298 which is actuated when the piston and pistonrod of the said cylinder reach the end of an unloading indexing stroke.The limit switch 298 is normally closed and is opened when actuated asdescribed. Thus, closing of the switch 342 results in energization ofthe solenoid 320 and operation of the air cylinder 266 to index theunloading wheel 200. A control relay CR2 which is connected in parallelwith the solenoid 320 is also energized when the switch 342 is closedand said relay in turn closes a normally open switch 344 which isconnected in parallel with the said switch 342. In closing, the switch344 shunts the switch 342 so as to maintain the solenoid 320 and itsrelay CR2 in an energized condition after the indexing movement of theunloading wheel 200 has been initiated and the workpiece thereby movedout of engagement with the pin 254 to open the circuit to ground throughthe switch armature 246 and dc-energize the electronic relay 340. Thereis also connected in parallel with the limit switch 298 and the relaycontrol switches 342 and 344, a manually operable switch 346. The switch346 is normally open for automatic operation of the grinding machine butmay be closed by the machine operator to energize the solenoid 320 andthereby to index the unloading wheel 200.

While the wheel indexing movement of the air cylinder 266 is inprogress, the limit switch 300, which is actuated when the piston andpiston rod of said cylinder are in the retracted position, is closed andwhen said piston and piston rod are retracted the said switch is open.The switch 300 is connected in circuit with the push button operatedswitch 330 and the solenoid 314 which effects feed strokes of thedelivery rod 40. Located between the switch 300 and the push buttonoperated switch 330 is a normally open switch 348. The switch 348 iscontrolled by the control relay CR2 and is closed when the said relay isenergized. Thus, it will be seen that when the solenoid 320 is energizedto initiate an indexing stroke of the air cylinder 266, the switch 348will be closed. As the indexing stroke of the piston and piston rod ofthe air cylinder 266 begins, the limit switch 300 will also be closedand if the push button operated switch 330 is closed for automaticoperation of the machine the solenoid 314 will be energized to initiatea feed stroke of the delivery rod 40. It the push button operated switch330 is open for single cycle operation of the machine, closing of theswitches 300 and 348 will, of course, have no effect.

It will be apparent that by providing the two switches and 3 48 incircuit with thesolenoid- 3-14, initiation of a feed strokeof the [rod40 and a new cycle of machine operation is made} dependent upon theabsence of a workpiece in the grinding'throat which might interfere withthe proper delivery of a succeeding workpiece to said throat; Thesolenoid 3134f cannot be energized to initiate a cycleof operationunless both of said switches are closed. When both of the siwitches300and 348 are closed, it is known thatthe control relay CR2 and thus thesolenoid 320 has ,heen properly ,energizd and it is further known thatan" indexing movement of the air cylinder 266 has been initiated; Oncesuch -a movement of the said cylinder has been initiated, it mayreasonably be expected that said movement will be completed and that theworkpiece which has set the unloading'apparatus in operation willgbeproperlylifted from the grinding throat so as not, to interfere with asucceeding workpiece.

The inventionclaimed-is:

l. A work loading apparatus for a centerless grinder of the type adaptedfor through-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, v said apparatus comprising meansdefining agenerally longitudinal d'eli'verychannel having its dischargeendadjacent the entry of the grinding throat, a longitudinallyreciprocahle delivery rod for successively thrusting workpieces alongthe delivery channel toward its discharge end and at least partlyentering the workpieces in said grinding throat, a hopper adapted tohold a stacked supply of workpieces with their axes generallylongitudinal and having a generally longitudinal slot in a lower portionthereof for the gravity discharge of said workpieces, anagitator'associated with the hopper comprising a pivotally supportedagitating member engaging the workpieces in a lower portion of thehopper and operating meansfor intermittently actuating said member sothat it ispivoted toward the workpieces to effect relative movementbetweenthemwhereby to prevent bridging and interlocking of theworkpieces and to insure that they'may fall freely through said hopperdischarge slot, a receiver disposed beneath the hopper and above thedelivery channel and adapted toacc'ept workpieces one at a time fromsaid hopper discharge slot-and to deposit said workpieces one at a timeinvs'aidl delivery channel for delivery to the grinding throat: by saidrod",.and intermittent drive means for operating said receiver todeposit workpieces in the delivery channel in timed; relation with thereciprocal movement of saidirod.

2. A work loading apparatus: asset forth in: claim 1whereinetherpivot-ally supported agitating member extends longitudinallyadjacent andrin engagement with theworkpiccesin-a lower portion-of thehopper and wherein said member, is provided with at least onelongitudinal do which engages and provides, a lifting, action on theworkpieces to effect relative movement therebetween when the agitatingmemberis pivoted by its operating means.

, 3. A work loadingapparatus fora centerless grinder ofthe type adaptedfor through-feed operation by longitudinal movement of workpieces inthe: grinding throat of themachine, saidlapparatus comprising meansdefining a generally longitudinal delivery channel. having its dischargeend adjacent' the? entry of the grinding throat, a longitudinallyreciprocable delivery rod for thrusting workpieces along; the deliverychannel toward its discharge end and at least partly entering theworkpiecesin said grinding throat, operating means for reciprocatingsaid rod, adapted tohold astacked supply of workpieces withrthcir axesgenerally: longitudinal and having a gen,- erally longitudinal slot ina: lower portion thereof for the: gravity discharge ofsaid; workpieces;an agitator associated with the v hopper comprising: a pivotallysupported agitating member engagingthe workpieces in a lower portion ofthe hopper andicomprising' operating means for actuating saidmembentopivot thesame toward the'workpieces and efiect relative movementbetween'themawhereby to prevent bridging and interlocking of theworkpieces and to insure that they may fall freely through said hopperdischarge slot, a receiver disposed beneath the hopper and above thedelivery channel and comprising a flute-d cylinder supported forrotation about a longitudinal axis Within a housing having longitudinalslots in upper and lower portions thereof respectively for receivingworkpieces from said; hopper discharge slot and for dischargingworkpieces to said delivery channel, a ratchet wheel and pawl deviceconnected with said fluted cylinder and operable when actuated to rotatesaid cylinder through a selected angle so that one of said cylinderflutes registers with" said upper housing slot to receive a workpiecefrom the "hopper discharge slot while an opposite flute registers withsaid lower housing slot to discharge a workpiece to the deliverychannel, operating means for actuating said ratchet wheel and pawldevice, and electrical control means for intermittently actuating saiddelivery rod operating means and said ratchet wheel and pawl operatingmeans and said agitator operating meansin timed relation with eachother.

4. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throarof the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rotationabout a substantially horizontal axis adjacent thedischarge end of the grinding throat and having at: least one generallyradial passage adapted to receive the projecting end portion of aworkpiece, and means operable when a; workpiece has reached saidpreselected position inthe grinding throat and when its projecting endportion has entered said passage to rotate the wheel so that saidworkpiece is lifted upwardly from the grinding throat.

5. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machine.when'the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rotation about a substantially horizontal axis adjacentthe discharge end of the grinding throat and having a plu rality ofgenerally radial passages each adapted to re ceive the projecting endportion of a workpiece, and intermittent drive means for rotating theunloading wheel so that said passages move upwardly into longitudinalregistry with the discharge end of the grinding throat in succession andso that the projecting ends of successive workpieces are entered in saidradial passages as they register with said throat discharge end, thesaid workpieces being thereby lifted upwardly from the grinding throatin succession as they reach said preselected position in the throat.

6. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the marhine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rotation about a substantially horizontal axis adjacentthe discharge end of the grinding throat and having a plurality ofgenerally radial passages each adapted to receive the projecting endportion of a workpiece, intermittent drive means for rotating theunloading wheel so that said passages move upwardly into longitudinalregistry with 19 the discharge end of the grinding throat in successionto receive the projecting end portions of successive workpieces as theyare advanced to said preselected position in said throat, the saidworkpieces thus being lifted upwardly from said grinding throat insuccession, and electrical control means operable to cause saidintermittent drive means to rotate said unloading wheel when a workpiecereaches said preselected position in the grinding throat wherein itsprojecting end portion is entered in an unloading wheel passage.

- 7. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rotation about a substantially horizontal axis adjacentthe discharge end of the grinding throat and having a plurality ofgenerally radial passages each adapted to receive the projecting endportion of a workpiece, intermittent drive means for rotating theunloading wheel so that said passages move upwardly into longitudinalregistry with the discharge end of the grinding throat in succession toreceive the projecting end portions of successive workpieces as they areadvanced to said preselected position in said throat, the saidworkpieces thus being lifted upwardly from said grinding throat insuccession, and automatically operable locking means for positivelypreventing rotation of said unloading wheel when said intermittent drivemeans is not operable to rotate same.

8. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected,

position in the throat and project from the discharge end apparatuscomprising a work unloading wheel supported for rotating about asubstantially horizontal axis adjacent the discharge end of the grindingthroat and having a plurality of generally radial passages each adaptedto receive the projecting end portion of a workpiece, an indexing wheelconnected in driving relationship with the unloading wheel and adaptedto be rotated through a selected angle by a pawl whereby to rotate saidunloading wheel through a similar angle and cause adjacent radialpassages in said wheel to move upwardly out of longitudinal registrywith the discharge end of the grinding throat and to move into registrywith said throat discharge end, a pawl for rotating the indexing wheel,and operating means for intermittently actuating said pawl to rotate theindexing and unloading wheels whereby said unloading wheel passages arecaused to register with the discharge end of the grinding throat insuccession for receiving the projecting end portions of successiveworkpieces as they are advanced to said preselected position in saidthroat, the said workpieces thus being lifted upwardly from saidgrinding throat in succession.

9. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove work pieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rotation about a substantially horizontal axis adjacentthe discharge end of the grinding throat and having a plurality ofgenerally radial passages each adapted to receive the projecting endportion of a workpiece, an indexing wheel connected in drivingrelationship with the un1oad ing wheel and adapted to be rotated throughaselected angle by a pawl whereby to rotate said unloading'wheel througha similar angle and cause adjacent radial passages in said wheel to moveupwardly out of longitudinal registry with the discharge end of thegrinding throat and to move into registry with said throat dischargeend, a pawl for rotating the indexing wheel, operating means forintermittently actuating said pawl to rotate the indexing and unloadingwheels whereby said unloading wheel passages are caused to register withthe discharge end of the grinding throat in succession for receiving theprojecting end portions of successive workpieces as they are advanced tosaid preselected position in said throat, the said workpieces thus beinglifted upwardly from said grinding throat in succession, and lockingmeans actuated by the pawl and operable to determine positively theangle through which the indexing and unloading wheels are rotated whensaid pawl is actuated by its operating means and operable also toprevent rotation of said indexing and unloading wheels when said pawl isnot actuated to rotate the same.

10. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat of the machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading wheelsupported for rota: tion about a substantially horizontal axis adjacentthe discharge end of the grinding throat and having a plurality ofgenerally radial passages each adapted to receivethe projecting endportion of a workpiece, intermittent drive means for rotating theunloading wheel so that said passages move upwardly into longitudinalregistry with the discharge end of the grinding throat in succession to'receive the projecting end portions of successive work pieces as theyare advanced to said preselected position in said throat, the saidworkpieces thus being lifted upwardly from said grinding throat insuccession, electrical control means operable to cause said intermittentdrive means to rotate said unloading wheel, and switch means adapted tobe operated by a workpiece when the workpiece reaches said preselectedposition in the grinding throat to actuate said electrical control meanswhereby to cause said wheel to be rotated.

11. In a centerless grinding machine of the type which is adapted forthrough-feed operation by longitudinal movement of workpieces in thegrinding throat ofthe machine, a work unloading apparatus adapted toremove workpieces successively from the grinding throat of the machinewhen the workpieces have reached a preselected position in the throatand project from the discharge end thereof during a through-feedgrinding operation, said apparatus comprising a work unloading Wheelsupported for rotation about a substantially horizontal axis adjacentthe' discharge end of the grinding throat and having a plural in saidthroat, the said workpieces thus being lifted up-.

wardly from said grinding throat in succession, electrical control meansoperable to cause said intermittent drive means to rotate said unloadingwheel, "and switch means for operating said electrical control means tocause "said wheel to be rotated and comprising an armature movableto oneposition wherein said electrical control means is so operated and alsocomprising a member connected with the armature and adapted to beengaged by a workpiece to move the said armature to its said oneposition, said member being disposed in said annular groove in theunloading wheel so as to project into each of the radial passages insaid wheel and into the path of the projecting ends of the workpieces assaid passages register in succession with the discharge end of thegrinding throat.

References Cited in the file of this patent UNITED STATES PATENTSHeckethorn July 10, 1945 Heckethorn Oct. 18, 1955 Cleifi May 7, 1957Silven Sept. 10, 1957 Seidel Nov; 17, 1959 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Paterit Nov, 2 990,656- July 4, 1961' AlbertH. Tompkins It is hereby certified that error appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below,-

Column 1,7 'line 6'7 after "rod insert, a hopper Signed and sealed this21st day of November 1961.

(SEA L) Attest:

ERNEST W. 'SWIDER Attesting Officer DAVID L ..LADD Commissioner ofPatents USCOMM-DC

